Recess filling mastic applicator having four point contact with surface and novel tool-steering means

ABSTRACT

A recess filling mastic applicator having a four point contact with a flat surface and novel tool-steering means in which the interior of the tool body receives mastic and a pressure plate is pivotally mounted in the body and is provided with a handle so that the operator can grasp the handle and press the tool body against the flat surface for applying pressure on the plate for forcing mastic from the tool to fill the recess in the surface. A trowelling blade is positioned adjacent to the mastic outlet opening of the tool and at the trailing end of the body. The blade has a concave edge so that only the two ends of the blade will contact with the surface and this will cause the blade to form a slight crown effect to the mastic layer that is applied to the surface for filling the recesses in the wall surface. A pair of spaced apart wheels are disposed at the leading end of the body and these wheels have circumferential grooves for receiving rubber tires. The operator can apply a twisting or lateral force to the handle for urging the leading end of the tool body to the right or to the left and the portions of the tires contacting with the wall surface will be warped laterally to permit the direction of the tool movement to be altered. In this way the operator can steer the tool.

United States Patent 1 Ames 1 1 RECESS FILLING MASTIC APPLICATOR HAVING FOUR POINT CONTACT WITH SURFACE AND NOVEL TOOL-STEERING MEANS [75] Inventor: Robert G. Ames, Hillsborough.

Calif.

[73] Assignee: Ulysses Stanley Ames, San Carlos,

Calif.

[22] Filed: July 22, 1974 [21] Appl. No.: 490,769

Primary ExaminerRobert L. Spicer, Jr. Attorney, Agent, or FirmWilliam R. Piper [H1 3,888,611 June 10, 1975 [5 7] ABSTRACT A recess filling mastic applicator having a four point contact with a flat surface and novel tool-steering means in which the interior of the tool body receives mastic and a pressure plate is pivotally mounted in the body and is provided with a handle so that the operator can grasp the handle and press the tool body against the flat surface for applying pressure on the plate for forcing mastic from the tool to fill the recess in the surface. A trowelling blade is positioned adjacent to the mastic outlet opening of the tool and at the trailing end of the body. The blade has a concave edge so that only the two ends of the blade will contact with the surface and this will cause the blade to form a slight crown effect to the mastic layer that is applied to the surface for filling the recesses in the wall surface. A pair of spaced apart wheels are disposed at the leading end of the body and these wheels have circumferential grooves for receiving rubber tires. The operator can apply a twisting or lateral force to the handle for urging the leading end of the tool body to the right or to the left and the portions of the tires contacting with the wall surface will be warped laterally to permit the direction of the tool movement to be altered. In this way the operator can steer the tool.

6 Claims, 9 Drawing Figures 1 RECESS FILLING MASTIC APPLICATOR HAVING FOUR POINT CONTACT WITH SURFACE AND NOVEL TOOL-STEERING MEANS BACKGROUND OF THE INVENTION 1. Field of the Invention wallboard sections are secured to wall studs by screwing or nailing the wallboard to the studs and joists. The nail heads are forced below the surface of the wallboard and this leaves a row of recesses parallel- 1 ing the stud which must be filled with mastic. In addition, the edges of the layer of mastic must be feathered into the adjacent wallboard surface so as to hide the re cesses. My present tool is designed for accomplishing this purpose. If the tool body is not in perfect alignment with the row of recesses that are to be filled, the movernent of the tool over the wallboard surface will cause the tool to apply the layer of recess covering mastic so that the layer will not parallel the row of recesses. The operator can correct the direction of travel of the tool body by twisting or urging the handle to the right or left and the rubber tires on the front wheels will have their wallboard contacting portions warped laterally to per mit the tool body to correct its direction of travel as it is moved along the row of recesses in the wallboard sur face.

2. Description of the Prior Art The patent to Robert G. Ames, US. Pat. No. 2,809,5l3, issued Octv I5, 1957, on a Recess-Filling Applicator, discloses a tool body with a trowelling blade at its trailing end and a triangularly shaped shoe at its forward end. The apex of the shoe extends rearwardly and is attached to the bottom of the tool body. The front edge of the shoe extends at right angles to the direction of travel of the tool. A spacer knob is placed between the shoe and the tool bottom and is centered with respect to the sides of the tool. The surface of the knob that faces the shoe is made convex so that the front or leading edge of the shoe can rock laterally on the knob as the tool body is moved over the wallboard surface. This leading edge of the shoe frictionally contacts with the surface providing a one point contact with the surface while the ends of the trowelling blade contact with the same surface giving the tool a three point contact with the wallboard surface.

In the present invention a four point contact between the tool body and the wallboard surface is effected and these four points comprise the two ends of the trowelling blade that are placed at the trailing end of the body, the blade having the concave lower edge; and the two wheels that are spaced apart and are arranged at the forward end of the body. The wheels overcome any friction of the tool body as it moves over the wallboard surface because they take the place of the shoe disclosed in the abovementioned patent. Furthermore, the rubber tires on the two wheels permit the steering of the too] body as it is moved because the tire portions contacting with the wallboard surface can be warped laterally as a lateral steering force is applied to the tool handle by the operator and in this way he can guide the tool body so it will parallel the row of recesses in the wall. The rubber tire serves another function of absorbing surface irregularities that might reduce presure on the ends of the trowelling bar, thus reducing the quality of the feathered edges.

SUMMARY OF THE INVENTION An object of my invention is to provide a recess filling mastic applicator having a four point contact with the surface over which the tool is moved. Two of these points of contact are the two wheels placed at the forward end of the tool and having peripheral grooves provided with rubber tires. The tool body has a pressure plate pivotally mounted therein and a handle is pivot- 0 ally connected to the pressure plate in a manner that will permit the plate and body to swing laterally with respect to the handle as the tool body moves over any uneven surface areas. The pivotal connection of the handle to the pressure plate is such that if the operator twists and/or moves the handle laterally either to the right or to the left as the handle moves the tool body over the wallboard surface, the forward end of the body will be likewise urged toward the right or to the left. The portions of the rubber tires on the front wheels that contact with the surface will be warped to the right or to the left in correspondence to the lateral or twisting pressure on the handle and in this way the direction of the movement of the tool body over the surface can be corrected.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a side elevation of the device.

FIG. 2 is a top plan view of FIG. 1.

FIG. 3 is a longitudinal section taken along the line 33 of FIG. 2. The handle is not shown in FIG. 3.

FIG. 4 is a bottom plan view of the device.

FIG. 5 is a transverse section through the pivotal connection between the handle and the pressure plate and it is taken along the line 5-5 of FIG. 2.

FIG. 6 is an enlarged front elevation of the matrix and the trowelling blade carried by the matrix. The Fig ure further illustrates a portion of the tool body and further shows a section through a piece of wallboard and how the wallboard is secured to a stud by a nail, the nail head being received in a recess in the wallboard surface. It is this recess that is covered by a mastic layer.

FIG. 7 is a diagrammatic showing of the four point contact made by the tool body with the surface over which the body is moved. It further illustrates how the tool body can be steered by swinging the handle to the right or to the left.

FIG. 8 is an enlarged transverse section through one of the wheels with its rubber tire received in its annular groove.

FIG. 9 is a view similar to FIG. 8 and it illustrates how the portion of the tire contacting the surface over which the tool body moves is warped to the left when the tool handle is swung to the right in FIG. 7 for guid ing the front end of the tool body to the right without sliding the wheels sideways.

DESCRIPTION OF THE PREFERRED EMBODIMENT In carrying out my invention I provide a tool body in dicated generally at A in FIGS. 1 to 4 inclusive. The body has two side walls 1 and 2 of the shape shown in FIG. I. A rigid bottom plate 3, see FIGS. 3 and 4, is placed between the two side walls 1 and 2 and it has lat erally extending projections 4, see FIG. 1, extending along its side edges and received in openings 5 provided in the side walls 1 and 2. An arcuate-shaped front wall 6, see FIG. 3, is positioned between the side walls I and 2 and it has laterally extending projections 7, see FIG. 1, extending along its side edges and received in openings 8 provided in the side walls I and 2. The rigid bottom 3 has a mastic outlet opening 9 of the size and shape shown in FIGS. 3 and 4. A shoe B is secured to the underside of the bottom 3 by screws 10 and it has a recess 11 of the same size and shape as the opening 9 in the bottom 3. The shoe is wedgeshaped in cross section as is shown in FIG. 3 and it has outwardly extending projections 12 and 13 as is clearly shown in FIG. 4. These projections protect the ends of the matrix holding the brittle carbide trowelling blade which will be described hereinafter. FIG. 1 illustrates how the lower rear edges of the sides 1 and 2 are recessed at 14 to receive the projections 12 and 13.

I pivotally mount a mastic pressing plate C between the sides 1 and 2 of the body A, see FIG. 3, and screws 15 rigidly secure the forward end of the plate C to a transversely extending shaft D whose ends are journalled in the body sides 1 and 2. A rubber seal E is angle-shaped in cross section and it has a plurality of spaced integral projections I6, see also FIG. 4, that are received in openings 17 in the bottom plate 3 for an choring the rubber seal to the plate. The rubber seal E extends from the bottom plate 3 to the transversely extending shaft D and it has a length equal to the distance between the two side walls 1 and 2 of the body A. The purpose of the rubber seal is to prevent any leakage of mastic through the space lying between the shaft D and the bottom 3 of the body A. The pressure of any mastic against the rubber seal E as the pivoted plate C is moved for exuding mastic through the outlet opening 9 in the bottom 3 will force the seal more tightly against the shaft to prevent any leakage.

The undersurface of the mastic pressing plate C is provided with a U-shaped rubber seal F, see FIGS. 1, 2 and 3 and this seal is arranged along the two side edges and the rear edge of the plate C. This rubber seal F is angle-shaped in cross section and it has integral and spaced apart projections 18 on the portion that contacts the undersurface of the plate C and these projections are received in openings I9 in the plate C, see FIGS. 2 and 3, for securing the seal to the plate. The center for the radius for the arcuate rear wall 6 of the body A coincides with the axis of the transverse shaft D to which the plate C is attached. Therefore, the portion of the rubber seal F that contacts with the inner surface of the arcuate portion of the rear wall 6 will be pressed against this inner surface when the plate C is swung inwardly as will be hereinafter described and no leakage of mastic past this portion of the seal will take place. Also, the opposite parallel side portions of the U-shaped rubber seal F will contact the inner surfaces of the body side walls 1 and 2. Again, these side portions of the rubber seal F will be pressed against the adjacent surfaces of the body sides I and 2 and will prevent any leakage of mastic past the seal during the swinging movement of the plate C toward the bottom plate 3 of the body A.

Before describing the handle and how it is connected to the swingable plate C, it is best to first set forth the four point contact the body A has with the surface over which the body is moved. Two of these four points of contact are provided at the ends of a trowelling blade G that is mounted on the body A adjacent to the curved rear wall 6, see FIGS. 3 and 4. In FIG. 6, I illustrate a front elevation of the matrix H that receives the carbide blade G in the groove 20. The matrix has an integral flange 21, as shown in FIGS. 3 and 6 and this flange is secured by screws 22 to the arcuate rear wall 6 of the body A so that the trowelling blade G will be positioned adjacent to the opening 9 of the bottom plate 3 and form the rear edge of this opening.

FIG. 6 illustrates the lower edge 23 of the trowelling blade G as being slightly concave and the edge extends below the matrix H whereby only the two ends 23a of the blade G will contact with the surface 24 of a wallboard J. These are two of the four points of contact between the tool body A and the surface 24. The flange 21 of the matrix extends between the two side walls I and 2 of the tool body while the portion of the matrix that holds the blade G extends slightly beyond the sidewalls. The laterally extending projections 12 and 13 of the shoe B abut the adjacent side of the matrix H so as to protect it and the blade G, see FIG. 4. The shoe is wedge-shaped in longitudinal cross section, as is shown in FIG. 3, and the thin edge of the shoe is at the trailing end of the shoe and it is this thin edge that contacts the side of the matrix to protect the blade.

The carbide blade G is brittle and can be easily chipped or broken. The blade is cemented in the matrix groove. In some building structures, wallboard is secured to steel studs rather than wood studs and screws rather than nails are used to secure the wallboard to the steel stud. Sometimes the screw head projects above the outer surface of the wallboard and if the unprotected carbide blade should strike the screw head, the blade would be broken. My matrix protects the carbide blade since only the lower concave edge 23 extends a slight distance below the lower edge of the matrix, see FIG. 6. The head of the nail 49 might also in certain cases project above the recess and the purpose of the matrix is to protect the carbide trowelling blade G should it by chance strike an exposed nail head or screw head. FIGS. 1 and 2 show the side walls 1 and 2 provided with recesses for receiving the ends of the matrix H. The edges of the recesses 55 do not tightly grip the adjacent surfaces of the matrix and, therefore, this will permit a slight flexing of the matrix and the blade without the trowelling blade breaking.

The other two points of the four points of contact between the tool body A and the wallboard surface 24 consist of the two wheels K and L that are rotatably mounted on a transversely extending stationary shaft M which extends between the side walls 1 and 2 of the tool body A, see FIG. 4. Both wheels K and L are identical to each other and, therefore, a detailed description of the wheel K will suffice for both and similar features will be given duplicate reference numerals. In FIG. 8, I show the stationary shaft M with a reduced cylindrical portion 25 and the wheel K rotates freely on this portion. The outer end of the reduced portion 25 abuts the adjacent inner surface of the side wall 1 of the tool body A and the shaft end has an axial threaded bore 26 for receiving a screw 27 that is inserted in an opening 28 in the side 1 of the tool body A. The wheel K has an annular groove 29 therein for receiving a rubber tire 30. It should be noted that the width of the annular groove 29 is wider than the width of the rubber tire so as to permit the slight warping of the tire portion that contacts the wallboard surface 24 either to the right or to the left when the lateral force is applied to the tool body A either to the right or to the left. This important feature will be explained more fully when setting forth the operation of the device.

In FIGS. I to 5 inclusive I illustrate how a handle N is pivotally attached to the mastic pressing plate C. The handle has a rigid rod 31 extending from the inner end of the handle and it is bent in the manner shown in FIG. 2 to form an axle portion 32 that is rockably received in the bore 33 of a bracket P shown in FIGS. 3 and 5. Metal washers 34 and 35 are mounted on the axle portion 32 of the rod 31 and they will frictionally contact with both of the flat sides of the bracket P so as to frictionally hold the handle N in the angle into which it has been swung with respect to the mastic pressing plate C. The rod 31 is welded to the metal washer 34 and this washer has a tongue 36 extending radially from the periphery of the washer and is bent at right angles at 36a. The metal washer 35 has a U-shaped integral projection 37 extending from its periphery and receiving the bent end 360 of the tongue 36. In this way the two metal washers are interlocked together so as to rotate together when the handle N and rod 31 are swung into different angular positions.

It is possible to alter the friction made between the metal washers 34 and 35 and the adjacent faces of the bracket P that extends between the two washers. The end of the axle portion 32 of the rigid rod 31 is threaded at 32a and receives a nut 38 whose cylindrical periphery is knurled. A bell washer 39 is interposed between the nut 38 and the metal washer 35 and will exert the desired degree of pressure on the washer 35 in accordance with how tight the nut presses against the bell washer. As the pressure of the bell washer 39 is increased by tightening the nut 38 on the threaded portion 32a so is the pressure increased by both washers 34 and 35 against the adjacent faces of the bracket P. The knurled nut 38 can be readily adjusted with the fingers.

FIGS. 3 and 5 illustrate how the bracket P is secured to the mastic pressing plate C so that the bracket can swing laterally to a slight extent with respect to the plate C. A cross section through the bracket I shows that the lower edge of the bracket is rounded at 40 so that this edge will permit the bracket P to rock laterally, see FIG. 5. A plurality of studs 41 are threaded into threaded bores 42 in the bracket P and these studs extend through enlarged openings 43 in the plate C and also extend through an elongated rubber washer 44. Nuts 45 are threaded onto the studs 41 and clamp the bracket P and the washer 44 to opposite faces of the plate C. The enlarged openings 43 in the plate C and the rubber washer 44 permit the bracket P to swing laterally as indicated by the inclined dot-dash lines 45 and 46 in FIG. 5. The washer or shim 44 prevents mastic from passing through the openings 43.

A screw 47 is carried by the side wall I of the tool body A and limits the swing of the mastic pressing plate C away from the bottom plate 3, see FIGS. 1 and 2. An angle-shaped member Q is attached to the underside of the bottom plate 3 and projects forwardly of the leading edge of the plate 3. This member 0 is angle-shaped in cross section see FIG. 3, and has a portion extending downwardly. The front edge 48 of the member Q makes it easier for the operator to adjust the position of the tool body A on the wallboard surface 24 should the tool be out of position after the last stroke the operator made to apply a layer of mastic over a row of recesses in the wallboard.

OPERATION From the foregoing description of the various parts of the device, the operation thereof will be readily understood. The interior of the body A is filled with mastic by injecting the mastic through the outlet 9 of the tool. The mastic will force the pivoted plate C up against the stop screw 47 shown in FIGS. I and 2. The tool is now loaded with mastic and is ready for use.

FIG. 6 shows a piece of wallboard .I secured to a stud R by a row of nails. one of the nails 49 being shown in the Figure as extending through the wallboard and into the stud. The nail head is forced into the wallboard surface 24 and forms a recess 50. It is this row of recesses my tool is designed to fill by a layer of mastic that extends over the row and the edges of the mastic layer will be feathered by the trowelling blade so as to merge into the wallboard surface.

It is difficult for the operator to make the tool body A follow a line that parallels the row of recesses 50 which are to be filled with mastic because the tool body when starting at the first recess in the row, if it should be the least bit out of alignment, will have a tendency to veer off to the side of the row and it might be considerably out of alignment at the end of the row. This is true because the tool body tends to hold to a straight line when it is moved by the operator and if this straight line does not parallel the row of recesses 50 then the operator must realign the tool to the row or start over again.

In my present invention I provide the novel steering means for the tool body which permits the operator to correct the linear movement of the body so as to keep it correctly following the line or row of recesses. FIG. 7 is a diagrammatic showing of the four points of contact the tool body makes with the wallboard surface. The tool body is not shown but the trowelling blade G is illustrated in top plan view and since the under edge 23, see FIG. 6, is concave in shape only the two ends 23a of the blade will contact with the wall surface. The row of nails 49 and recesses 50 are shown in FIG. 7. The remaining two points of contact are the two front wheels K and L with their rubber tires 30 actually riding on the wallboard surface. The bracket P is also shown in FIG. 7 and a dot-dash line 51 represents the handle N that is pivotally connected to the bracket. The tool body is lined up with the row of recesses 50 in FIG. 7 and the operator moves the handle in the direction of the arrow 52 while pressing on the handle and mastic pressing plate C for forcing mastic out through the opening 9 in the bottom plate 3 and against the surface 24 of the wallboard .I. FIG. 6 illustrates how the concave lower edge 23 of the trowelling blade G will form the mastic into a layer that will cover the recesses 50 and nail heads 49 and will form a crowned upper surface to the mastic layer.

Should the tool body not be accurately aligned with the row of recesses 50 in FIG. 7, the tool will either tend to move to the left of the row or to the right of the row. If the tool body starts moving to the left then the operator will swing the handle N (illustrated by the dotdash line 51 to the right as shown by the inclined dotdash line 53 in FIG. 7. This will tend to swing the front end of the tool to the right. FIG. 9 illustrates what will happen to the rubber tire portion 30 when the tendency of the front end of the tool is to move to the right in FIG. 7. The tire portion that contacts with the wallboard surface 24 will be warped to the left as shown in FIG. 9 and since the same thing is happening to the rubber tires 30 on both of the front wheels K and L, the continued rotation of the wheels over the surface will permit the front of the tool body to steer to the right in FIG. 7 and to bring the tool body back into alignment with the row of recesses 50. As soon as the tool body is back into proper alignment the operator ceases to exert any more lateral thrust on the handle N. represented by the dot-dash line 53 in FIG. 7 to the rightv What I have explained for correcting the tool body movement when it starts to travel to the left in FIG. 7 holds true as to when the tool body tends to move to the right except that now the operator would swing the handle toward the inclined dot-dash line 54. The rubber tires 30 also absorb the high spots on the wallboard surface 24 without lifting the ends of the trowelling blade or bar off from the wall. This makes the three point suspension of the tool shown in US. Pat. No, 2,809,513, unnecessary.

The rounded lower edge 40 on the bracket P, see FIG. 5, permits the tool body to swing laterally with respect to the bracket so that the body can ride over any uneven surface of the wallboard J. The rubber shim or washer 44 allows lateral swinging of the bracket and handle. It also seals the mastic from moving through the openings 43 in the plate C. l have found that the brittle carbide blade G is less apt to be broken when the blade is held in a semi resilient matrix H.

I claim:

I. A recess filling mastic applicator comprising:

a. a body for receiving mastic and having spaced apart side walls, an arcuate rear wall, and a bottom wall having a mastic outlet opening disposed adjacent to the rear arcuate wall;

b. a mastic pressing plate having its front edge pivotally connected to said side walls, the side edges of said plate being disposed adjacent to the side walls and the rear edge of said plate lying adjacent to said arcuate rear wall;

c. a handle pivotally connected to said pivoted plate;

d. a trowelling blade extending transversely across the lower edge of said arcuate trailing wall and having an arcuate lower edge so that only the two ends of said blade will contact with the surface over which the tool is moved;

e. a pair of spaced apart wheels operatively connected to said side walls of the tool body, said wheels having rubber tires which contact with the surface; the pivotal connection between the handle and said plate including means for urging the front of the tool body to the right or to the left when the operator exerts a lateral thrust on the handle toward the right or toward the left while pressing on the handle to maintain the tool body in a four point contact with the surface;

g. whereby a lateral thrust of the handle to the right will cause the tool body front to swing toward the right so as to warp the rubber tire portions to the left that contact with the surface and permit the tool body to steer to the right and vice versa when the lateral thrust is to the left.

2. The combination as set forth in claim 1: and in which a. a matrix secured to said arcuate rear wall and having a groove for receiving said trowelling blade, the

arcuate lower edge of said blade extending beyond said groove;

b. said body side walls having recesses therein for receiving the ends of said matrix; and

c. a shoe underlying said bottom wall and having a recess whose edge coincides with the edge of the mastic outlet opening in said bottom wall, the trailing edge of said shoe abutting the adjacent surface of said matrix for protecting said trowelling blade.

3. The combination as set forth in claim I: and in which a. the means in said pivotal connection between the handle and said mastic pressing plate for urging the front end of the tool body to swing in the same direction as the handle when a lateral thrust is applied to said handle, includes;

b. an elongated bracket extending in the same direction as the length of said tool body and means for securing said bracket to said mastic pressing plate;

c. the pivotal connection between the handle and said bracket including a rod extending from the inner end of said handle and having a portion whose axis extends at right angles to the length of said tool body and is rockably received in said bracket to function as a shaft portion;

d. whereby a lateral thrust exerted on said handle will tend to swing the shaft portion of said rod and said bracket so as to urge the front end of the tool body in the same direction as the lateral thrust on said handle for steering the tool as the tool body is moved over the surface.

4. The combination as set forth in claim 3: and in which a. the means for securing said bracket to said plate includes a plurality of threaded studs projecting from the lower edge of said bracket and extending through openings in said plate; and

b. a rubber shim underlying said plate and having said studs pass therethrough and nuts tightened on said studs for securing the bracket and shim to said plate;

c. the lower edge of said bracket being convex in cross section so that said tool body and plate can rock laterally as the body moves over an uneven surface, the shim also preventing any mastic in the tool body from bleeding through the openings in said plate that receive said threaded studs.

5. The combination as set forth in claim 1: and in which a. said wheels have annular grooves for receiving the rubber tires, the wheel grooves having a width greater than the width of said tires so as to permit a lateral warping of the tire portions that contact with the surface over which the tool body moves when a lateral thrust on said handle tends to move the front end of the body in the same direction as the thrust against the handle, whereby an effective steering of the tool body is accomplished;

b. said rubber tires and the ends of said trowelling blade giving a four point contact between the tool body and the surface over which the tool body moves, the rubber tire portions that contact with the surface also being able to compress as the tool moves over the surface so that the wheels will not lift either end of said trowelling blade above the surface.

9 l 6. The combination as set forth in claim I: and in b. the sides and rear edge of said plate having a U- which shaped rubber seal that is secured to said plate and a. a rubber seal extends between said bottom wall slidably contacts the side walls and the arcuate rear and the pivotal connection for the mastic pressing wall of said body. plate to prevent any mastic from escaping; and 

1. A recess filling mastic applicator comprising: a. a body for receiving mastic and having spaced apart side walls, an arcuate rear wall, and a bottom wall having a mastic outlet opening disposed adjacent to the rear arcuate wall; b. a mastic pressing plate having its front edge pivotally connected to said side walls, the side edges of said plate being disposed adjacent to the side walls and the rear edge of said plate lying adjacent to said arcuate rear wall; c. a handle pivotally connected to said pivoted plate; d. a trowelling blade extending transversely across the lower edge of said arcuate trailing wall and having an arcuate lower edge so that only the two ends of said blade will contact with the surface over which the tool is moved; e. a pair of spaced apart wheels operatively connected to said side walls of the tool body, said wheels having rubber tires which contact with the surface; f. the pivotal connection between the handle and said plate including means for urging the front of the tool body to the right or to the left when the operator exerts a lateral thrust on the handle toward the right or toward the left while pressing on the handle to maintain the tool body in a four point contact with the surface; g. whereby a lateral thrust of the handle to the right will cause the tool body front to swing toward the right so as to warp the rubber tire portions to the left that contact with the surface and permit the tool body to steer to the right and vice versa when the lateral thrust is to the left.
 2. The combination as set forth in claim 1: and in which a. a matrix secured to said arcuate rear wall and having a groove for receiving said trowelling blade, the arcuate lower edge of said blade extending beyond said groove; b. said body side walls having recesses therein for receiving the ends of said matrix; and c. a shoe underlying said bottom wall and having a recess whose edge coincides with the edge of the mastic outlet opening in said bottom wall, the trailing edge of said shoe abutting the adjacent surface of said matrix for protecting said trowelling blade.
 3. The combination as set forth in claim 1: and in which a. the means in said pivotal connection between the handle and said mastic pressing plate for urging the front end of the tool body to swing in the same direction as the handle when a lateral thrust is applied to said handle, includes; b. an elongated bracket extending in the same direction as the length of said tool body and means for securing said bracket to said mastic pressing plate; c. the pivotal connection between the handle and said bracket including a rod extending from the inner end of said handle and having a portion whose axis extends at right angles to the length of said tool body and is rockably received in said bracket to function as a shaft portion; d. whereby a lateral thrust exerted on said handle will tend to swing the shaft portion of said rod and said bracket so as to urge the front end of the tool body in the same direction as the lateral thrust on said handle for steering the tool as the tool body is moved over the surface.
 4. The combination as set forth in claim 3: and in which a. the means for securing said bracket to said plate includes a plurality of threaded studs projecting from the lower edge of said bracket and extending through openings in said plate; and b. a rubber shim underlying said plate and having said studs pass therethrough and nuts tightened on said studs for securing the bracket and shim to said plate; c. the lower edge of said bracket being convex in cross section so that said tool body and plate can rock laterally as the body moves over an uneven surface, the shim also preventing any mastic in the tool body from bleeding through the openings in said plate that receive said threaded studs.
 5. The combination as set forth in claim 1: and in which a. said wheels have annular grooves for receiving the rubber tires, the wheel grooves having a width greater than the width of said tires so as to permit a lateral warping of the tire portions that contact with the surface over which the tool body moves when a lateral thrust on said handle tends to move the front end of the body in the same direction as the thrust against the handle, whereby an effective steering of the tool body is accomplished; b. said rubber tires and the ends of said trowelling blade giving a four point contact between the tool body and the surface over which the tool body moves, the rubber tire portions that contact with the surface also being able to compress as the tool moves over the surface so that the wheels will not lift either end of said trowelling blade above the surface.
 6. The combination as set forth in claim 1: and in which a. a rubber seal extends between said bottom wall and the pivotal connection for the mastic pressing plate to prevent any mastic from escaping; and b. the sides and rear edge of said plate having a U-shaped rubber seal that is secured to said plate and slidably contacts the side walls and the arcuate rear wall of said body. 